import java.util.StringJoiner;
public class test3 {
    public static void main(String[] args){
        StringJoiner sj = new StringJoiner(", ","[","]");
        String[] arr = {"1", "2", "3"};
        String str = "";
        for(int i = 0;i < arr.length;i++){
            str = sj.add(arr[i]).toString();
        }
        System.out.println(str);
    }
}
